Facts of the case

David Leon Riley belonged to the Lincoln Park gang of San Diego, California. On August 2, 2009, he and others opened fire on a rival gang member driving past them. The shooters then got into Riley's Oldsmobile and drove away. On August 22, 2009, the police pulled Riley over driving a different car; he was driving on expired license registration tags. Because Riley's driver's license was suspended, police policy required that the car be impounded. Before a car is impounded, police are required to perform an inventory search to confirm that the vehicle has all its components at the time of seizure, to protect against liability claims in the future, and to discover hidden contraband. During the search, police located two guns and subsequently arrested Riley for possession of the firearms. Riley had his cell phone in his pocket when he was arrested, so a gang unit detective analyzed videos and photographs of Riley making gang signs and other gang indicia that were stored on the phone to determine whether Riley was gang affiliated. Riley was subsequently tied to the shooting on August 2 via ballistics tests, and separate charges were brought to include shooting at an occupied vehicle, attempted murder, and assault with a semi-automatic firearm.

Before trial, Riley moved to suppress the evidence regarding his gang affiliation that had been acquired through his cell phone. His motion was denied. At trial, a gang expert testified to Riley's membership in the Lincoln Park gang, the rivalry between the gangs involved, and why the shooting could have been gang-related. The jury convicted Riley on all three counts and sentenced to fifteen years to life in prison. The California Court of Appeal, Fourth District, Division 1, affirmed.

Question

Was the evidence admitted at trial from Riley's cell phone discovered through a search that violated his Fourth Amendment right to be free from unreasonable searches?

This Court has said that as a general rule, a search for evidence of a crime requires a warrant in order to be reasonable.

There are however some exceptions to that general rule and the search can be reasonable even without a warrant if it falls within one of those exceptions.

The exception at issue here is one for searches incident to arrest.

When someone is lawfully arrested, the police may search him and the area immediately around him and inspect physical objects found on his person.

We have said that such a search serves two important purposes, removing weapons that the arrestee might use against an officer and discovering evidence that the arrestee might conceal or destroy.

In a case from 1973 called United States against Robinson, this Court held that those two interests categorically justify a search of the person being arrested without the need for an assessment of the risks presented in any given case.

As a result, the Court permitted a search of Robinson and of his cigarette pack found in his coat pocket which turned out to contain heroin capsules.

We do not disturb Robinson's holding today, but we decline to extend the search incident to arrest exception from a search of a physical item found on the arrestee to a search of the digital data on a cell phone in the arrestee's possession.

In the case of the cell phone, the government's interest in an immediate warrantless search is significantly diminished and the individual's privacy interest is dramatically expanded.

On the government interest side, there are as I've mentioned two justifications for a search incident to arrest.

Neither carries much weight when it comes to searches of cell phone data.

First, our cases have talked about the risk that an arrestee will have a weapon that can harm officers but the digital information stored on a phone does not itself pose any threat to police.

Second, there is a risk that an arrestee will conceal or destroy evidence on his person, but once the police have ceased a phone, the person being arrested can no longer delete evidence.

It is true that data on the phone might be susceptible to other kinds of tampering unique to the digital world such as remote wiping.

We think however that these unique problems are insufficient to justify a general exception to the warrant requirement.

Instead, they can be dealt with through law enforcement's own technological tools or through targeted responses to specific threats of data destruction.

Now when it comes to the individual's privacy interest on the other side of the balance, there really is no comparison between physical objects and the data on a modern cell phone.

In 1973, when the Robinson case was decided, a search of an arrestee's person was likely to be only a minor intrusion beyond the arrest itself.